title: Keratocyte apoptosis and not myofibroblast differentiation mark the graft/host interface at early time-points post-DSAEK in a cat model.
abstract: OBJECTIVE
  To evaluate myofibroblast differentiation as an etiology of haze at the graft-host interface in a cat model of Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK).
  
  
  METHODS
  DSAEK was performed on 10 eyes of 5 adult domestic short-hair cats. In vivo corneal imaging with slit lamp, confocal, and optical coherence tomography (OCT) were performed twice weekly. Cats were sacrificed and corneas harvested 4 hours, and 2, 4, 6, and 9 days post-DSAEK. Corneal sections were stained with the TUNEL method and immunohistochemistry was performed for α-smooth muscle actin (α-SMA) and fibronectin with DAPI counterstain.
  
  
  RESULTS
  At all in vivo imaging time-points, corneal OCT revealed an increase in backscatter of light and confocal imaging revealed an acellular zone at the graft-host interface. At all post-mortem time-points, immunohistochemistry revealed a complete absence of α-SMA staining at the graft-host interface. At 4 hours, extracellular fibronectin staining was identified along the graft-host interface and both fibronectin and TUNEL assay were positive within adjacent cells extending into the host stroma. By day 2, fibronectin and TUNEL staining diminished and a distinct acellular zone was present in the region of previously TUNEL-positive cells.
  
  
  CONCLUSIONS
  OCT imaging consistently showed increased reflectivity at the graft-host interface in cat corneas in the days post-DSAEK. This was not associated with myofibroblast differentiation at the graft-host interface, but rather with apoptosis and the development of a subsequent acellular zone. The roles of extracellular matrix changes and keratocyte cell death and repopulation should be investigated further as potential contributors to the interface optical changes.
authors.affiliation: University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Weis
authors.forename: Krystel R
authors.initials: KR
authors.lastname: Huxlin
authors.forename: Christine L
authors.initials: CL
authors.lastname: Callan
authors.forename: Margaret A
authors.initials: MA
authors.lastname: DeMagistris
authors.forename: Holly B
authors.initials: HB
authors.lastname: Hindman
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002415:Cats; D002454:Cell Differentiation / Q000502:physiology; D003315:Cornea / Q000166:cytology / Q000473:pathology*; D060527:Corneal Keratocytes / Q000502:physiology*; D057111:Descemet Stripping Endothelial Keratoplasty / Q000009:adverse effects*; D058628:Myofibroblasts / Q000502:physiology; D018709:Statistics, Nonparametric; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology